Orbital fluid pump

ABSTRACT

An orbital fluid pumping mechanism ( 37 ) having an outer tube ( 12 ) and an inner member ( 14 ) positioned substantially concentrically within the outer tube. Helical lobes ( 18, 22 ) form sealed pumping chambers to move the fluid.

TECHNICAL FIELD

[0001] The present invention is directed toward powered fluid flow apparatus and methods, more particularly to a fluid pump, compressor or expander which operates through orbital motion.

BACKGROUND ART

[0002] Pumps are a class of devices which compress and/or pump fluids. Pumps and compressors as a class of devices are critical to the construction of apparatus designed to mechanically implement the refrigeration cycle. As used herein, the concept of a fluid encompasses gases, liquids, and supercritical fluids. Compressors and pumps can be constructed in a wide variety of mechanical designs but all can be classified into two general categories, positive displacement and non-positive displacement. Positive displacement pumps and compressors act on a fluid by sequentially increasing and decreasing the volume of a compression chamber. Fluid is drawn into the chamber as its volume increases and compressed or pumped as its volume decreases. Reciprocating, rotary, screw, and scroll are representative examples of positive displacement type pumps or compressors.

[0003] Reciprocating designs consist of a cylindrical compression chamber enclosing a piston, which reciprocates along the axis of the cylinder, alternately increasing and decreasing the volume of the closed end of the chamber. The piston is typically connected to a crank shaft via a rod, which provides mechanical power to the piston, allowing it to pump or compress fluid within the chamber. Valves on the chamber head open and close to control the flow of fluid in and out of the compression chamber during each cycle.

[0004] Rotary designs consist of a cylindrical compression chamber that encloses a roller having a diameter smaller than the inner diameter of the chamber. The roller is mounted in an eccentric manner, to a central (on axis) rotating power shaft. As the shaft rotates, the roller maintains contact with the chamber wall providing a seal for the fluid in the annular volume. Each rotation draws fluid into the volume through the inlet port and discharges it through the outlet port. A spring-mounted vane maintains contact with the roller through its rotation, isolating each volume of fluid as it is drawn into and forced out of the chamber.

[0005] Scroll pumps and compressors consist of a cylindrical chamber, which encloses a pair of interlinked scrolls. One scroll is fixed to the chamber wall. The second is mounted, typically via a mechanical linkage, to a rotating power shaft. The shaft and linkage impart an orbital motion to the second scroll. As the second scroll moves with an orbital motion within the fixed scroll, fluid entering from ports in the chamber wall is trapped and compressed as it is forced radially inward to the center of the scrolls. The compressed fluid exits through a port located on axis, at the end of the chamber. This design has the benefit over reciprocating and rotary designs of not requiring any valves or vanes to control the flow of fluid through the chamber.

[0006] Screw designs consist of two counter-rotating shafts. Each shaft has a set of lobes, which interlink with the corresponding lobes on the other shaft. As the two shafts rotate, fluid is trapped in the volumes between adjacent lobes and the housing wall. The volume between adjacent lobes on one shaft is sealed and compressed by a lobe on the other shaft. This lobe isolates the trapped fluid volume as it moves from the inlet port on one end of the housing to the discharge port on the other end. This design also has the benefit over reciprocating and rotary designs of not requiring any valves or vanes to control the flow of gas through the chamber.

[0007] The most common non-positive displacement design pump/compressor is the turbine. It consists of a cylindrical chamber enclosing a rotating shaft having blades or vanes. The shaft rotates at high speed and the blades or vanes impart velocity or kinetic energy to the fluid within the chamber. Unlike positive displacement designs, the volume of the chamber remains constant during operation. Conversion of fluid kinetic energy to static pressure at the chamber exit provides compression of the fluid.

[0008] Many other compressor and pump designs have been developed, which are based on some variation of the above designs. All of the described designs are limited by mechanical features which add to the complexity of their design and operation. For example, reciprocating designs require valves in the cylinder head to control the flow of fluid in and out of the compressor chamber. In addition, a shaft must pass through a seal in the housing wall to provide power to the piston. This requires some combination of bearings, bushings, and seals.

[0009] Power is provided to the shaft(s) of screw, rotary, and scroll designs by an external power source, also requiring a seal where the shaft passes through the housing and couples to the external power source. These designs can have hermetic seals if power is supplied through a non-invasive (typically magnetic) coupling. Scroll designs require a mechanical assembly to provide power from a rotating shaft to the orbiting scroll. All of the above-described designs rely on mechanisms which include some combination of valves, vanes, rotating shafts with seals and bearings, and are driven by electric motors or some other source of rotational mechanical power.

[0010] An innovative positive displacement design is the vibrating reciprocating compressor. The vibrating reciprocating compressor consists of a cylindrical chamber and piston arrangement but the piston rod is attached to a flexing diaphragm or set of rings instead of a rotating shaft. Vibration of the diaphragm provides the motion required to compress fluid in the compression chamber. Vibrational power is provided to the diaphragm by an electromechanical actuator. This design has the advantage of a compression chamber that is inherently sealed and does not require bushings or seals to prevent leakage around the power shaft. This design also eliminates the need for an electric motor or other source of rotational power to drive the piston. Several variations of this design are described in the following U.S. patents: Penswick et al., U.S. Pat. No. 5,920,133; Fujisawa et al., U.S. Pat. No. 5,704,771; and Watanabe, U.S. Pat. No. 5,255,521.

[0011] Although the vibrating reciprocating compressor is a sealed design, it still requires valves to control fluid flow through the compression chamber and it is not mechanically balanced. The piston vibrates with varying linear momentum and there is a constant conversion of potential energy, which is stored in the deformation of the diaphragm, to the kinetic energy of the piston.

[0012] A second type of vibrating pump, which is based on a linear pumping action, is described in Hashimoto et al., U.S. Pat. No. 5,266,012. This pump consists of a column, which is mounted to fixed conduits at each end, with axially flexible attachments. An actuator, which is attached to the column, causes the column to vibrate along its axis and in line with the fixed conduits. Valves within the column allow fluid within the column to move in only one direction, as the column vibrates. This action results in a net movement or pumping of the fluid within the column from one fixed conduit to the other. This design requires valves to control the flow of fluid through the device and has varying linear momentum, again resulting in a mechanically unbalanced design. None of the pumps or compressors taught by the prior art is simultaneously operable without valves, hermetically sealed and mechanically balanced.

[0013] Each of the pump and compressor designs described above can be used to build and operate refrigeration devices, heat pumps or heat engines which operate on the refrigeration cycle.

[0014] Some key characteristics of mechanical designs which implement refrigeration cycles are that they consume mechanical work as they transfer thermal energy from a low-temperature reservoir to a high-temperature reservoir and that the flow of thermal energy is generally in one direction only. Heat pump cycles function in the same manner as refrigeration cycles except that heat pumps include the necessary valves and controls to allow thermal energy to flow in both directions (i.e., both reservoirs can function as the high or low temperature reservoir).

[0015] Heat engine cycles function as refrigeration cycles in reverse. Heat engine cycles contain most if not all of the components of refrigeration cycles. The fundamental difference between the function of heat engines and that of refrigerators is that heat engines generate mechanical work as they transfer thermal energy from a high-temperature reservoir to a low-temperature reservoir.

[0016] The pumps and compressors described above can each be used to implement a mechanical refrigeration device based upon the refrigeration cycle. However, the pumps and compressors described above each consist of a relatively complex assembly of moving components. Each design relies to a greater or lesser degree on valves to control fluid flow into and out of a compression chamber. Most designs require seals between the compression chamber and the input of motive force. Finally, some designs are also mechanically unbalanced. The present invention is directed toward overcoming one or more of the problems discussed above.

SUMMARY OF THE INVENTION

[0017] One aspect of the present invention is an orbital fluid pumping mechanism. The orbital fluid pumping mechanism has an outer tube and an inner member positioned substantially concentrically within the outer tube. A helical outer lobe is associated with the inner surface of the outer tube and a helical inner lobe is associated with the outer surface of the inner member. The inner and outer helical lobes are each continuous solid structures, but each maybe configured in multiple continuous helical turns having a select vertical separation between the loops. The orbital fluid pumping mechanism may have apparatus associated with the inner member or the outer tube which can cause either the tube or member and its associated lobe to orbit with respect to the other.

[0018] The inner and outer helical lobes can be configured such that they do not contact each other as orbital motion occurs. In this aspect of the invention, fluid is pumped by the action of an orbiting constriction formed between the adjacent surfaces of the lobes as orbital motion occurs.

[0019] In another aspect of the orbital fluid pumping mechanism, the inner and outer helical lobes can be configured such that they contact each other as orbital motion occurs, forming an orbiting seal. In this aspect of the invention, fluid is pumped by the action of the orbiting seal formed between the adjacent surfaces of the lobes as orbital motion occurs.

[0020] The mechanism which is used to impart orbital motion can be of any suitable type including mechanical linkages or electromagnetic drive mechanisms. Orbital motion can be imparted to the orbiting part by applying two periodic linear forces to the orbiting part along first and second transverse lines of action. The periodic linear forces are applied at substantially the same frequency, but phase shifted with respect to time such that the combined forces serve to drive the orbiting tube in a substantially circular or elliptical orbit. In addition, two periodic restorative forces may be applied to the orbiting part along the first and second lines of action. The restorative forces may be actively applied, or may be passive recoil forces caused by the elastic deformation of the orbiting part by the first and second periodic linear forces.

[0021] The apparatus driving the orbital motion may be an electromagnetic drive mechanism, and one or more sensors may be attached to the orbiting part to provide feedback to the drive mechanism. Optionally, a control circuit may receive the feedback and control the orbital motion through control of the periodic linear or periodic restorative forces.

[0022] Another aspect of the present invention is an apparatus similar to the orbital fluid pumping mechanism described above, but having only one lobe attached to either the inner surface of the outer tube or the outer surface of the inner member. In the single lobe aspect, no seal can form, and fluid is pumped as orbital motion occurs by the action of an orbiting constriction formed between the adjacent surfaces of the lobe and the exterior surface of the inner member or the inner wall of the outer tube.

[0023] A third aspect of the present invention is an apparatus for pumping fluid. The apparatus consists of a base and a cantilevered tube pair attached to the base. A cantilevered tube pair is formed when two tubes, one placed concentrically within the other are attached to the base at a fixed end of each tube, with the other ends left free to orbit. In addition a pumping mechanism is operatively associated with the inner and/or outer tubes. The apparatus for pumping fluid may have a mechanism associated with the cantilevered tube pair which will impart orbital motion to either or both of the inner or outer tubes. The apparatus for pumping fluid may also have an outer housing which in conjunction with the base forms a support structure. The pumping mechanism may be a single lobe or two lobe orbital fluid pumping mechanism as described above, but could be any pumping mechanism which operates with orbital motion, such as a scroll compressor head.

[0024] The mechanism which is used to impart orbital motion can be of any suitable type including mechanical linkages or electromagnetic drive mechanisms. Orbital motion can be imparted to the orbiting tube by applying two periodic linear forces to the orbiting tube along first and second transverse lines of action. The periodic linear forces are applied at substantially the same frequency, but phase shifted with respect to time such that the combined forces serve to drive the orbiting tube in a substantially circular or elliptical orbit. In addition, two periodic restorative forces may be applied to the orbiting tube along the first and second lines of action. The restorative forces may be actively applied, or may be passive recoil forces caused by the elastic deformation of the orbiting tube by the first and second periodic linear forces.

[0025] The apparatus for pumping fluid may be configured with more than one cantilevered tube pair attached to the base. The frequency of the periodic linear forces and the fundamental resonant frequency of a tube within a cantilevered tube pair can be made to match, or the fundamental resonant frequencies of the inner and outer tubes may be made to match with each other, and with the frequency of the periodic linear focus. The frequency match can be made by modifying the resonant frequency of a tube through material selection or proper sizing of the vibrating tube. In addition, the configuration of the cantilevered tubes with respect to the support structure and the timing of the periodic linear forces applied to each tube pair can be such that the net force and torque on the base is minimized or ideally equals substantially zero.

[0026] Another aspect of the present invention is also an apparatus for pumping fluid similar to that described above, but not necessarily based upon a cantilevered tube pair. In this aspect, the apparatus consists of an outer tube, an inner tube positioned substantially concentrically within the outer tube, a pumping mechanism associated with one or both of the inner and outer tubes and an apparatus designed to impart orbital motion to one or both tubes, forming an orbiting tube.

[0027] The apparatus for pumping fluid of this aspect may also have a support structure supporting the orbiting tube. The pumping mechanism may be an orbital fluid pumping mechanism as described above, but could be any pumping mechanism which operates with orbital motion, such as a scroll compressor head.

[0028] The mechanism which is used to impart orbital motion can be of any suitable type including mechanical linkages or electromagnetic drive mechanisms. Orbital motion can be imparted to the orbiting tube as described above by applying two periodic linear forces to the orbiting tube along first and second transverse lines of action. The periodic linear forces are applied at substantially the same frequency, but phase shifted with respect to time such that the combined forces serve to drive the orbiting tube in a substantially circular orbit. In addition, two periodic restorative forces maybe applied to the orbiting tube along the first and second lines of action. The restorative forces may be actively applied, or may be passive recoil forces caused by the elastic deformation of the orbiting tube by the first and second periodic linear forces.

[0029] The apparatus for pumping fluid may be configured with more than one orbiting tube associated with the support structure. The configuration of the orbiting tubes with respect to the support structure and the timing of the periodic linear forces applied to each orbiting tube can be such that the net torque on the support structure is minimized or ideally equals substantially zero.

[0030] Another aspect of the present invention is an orbital apparatus for recovering energy from a fluid stream. This type of apparatus is commonly known as an expander. The expander of the present invention consists of an outer tube and an inner member concentrically positioned within the outer tube such that an annular space is located between the outer tube and the inner member. A fluid stream inlet opens into the annular space, and a fluid stream outlet leads from the annular space. In addition a helical outer lobe is associated with the inner surface of the outer tube, and a helical inner lobe is associated with the outer surface of the inner member and further associated with the helical outer lobe. Each lobe is located in fluid communication with a fluid stream flowing between the fluid stream inlet, and the fluid stream outlet.

[0031] The inner and outer helical lobes may be configured such that a flow of fluid introduced at the inlet and flowing to the outlet will cause orbital motion in at least one of the inner member or the outer tube.

[0032] The expander aspect of this invention may have apparatus attached for recovering the energy from the orbital motion caused by the fluid flow. The apparatus for recovering energy may consist of a mechanical linkage or a generator consisting of a magnet and wire coil pair. The magnet and wire coil pair together form an inductive pair. The orbital expander may be operatively associated with a corresponding fluid compressor as described above to form the components of a refrigeration apparatus or heat engine.

[0033] Another aspect of the present invention is an apparatus for imparting orbital motion to any object. The apparatus consists of a mechanism for applying two linear periodic forces to the object along first and second transverse lines of action. The linear periodic forces are applied at substantially the same frequency, but phase shifted with respect to time such that the combined forces serve to drive the orbiting object in a substantially circular or elliptical orbit. In addition, two periodic restorative forces may be applied to the object along the first and second lines of action. The restorative forces may be actively applied, or may be passive recoil forces caused by the elastic deformation of the object by the first and second periodic linear forces.

[0034] The mechanism for applying the first and second linear periodic forces or the first and second restorative forces may be an electromagnetic drive mechanism, a mechanical linkage or other suitable source of an applied force. In addition at least one sensor maybe associated with the object to generate a feedback signal from the object relative to the orbital motion. The apparatus may also include a control circuit which can process the feedback from the sensor to create a drive signal for the drive mechanism. The drive signal may be provided to the drive mechanism as a current which is continuously variable in a periodic fashion with respect to time, or the drive signal may be provided to the drive mechanism as a plurality of pulsed currents.

[0035] A still further aspect of the present invention is a method of imparting orbital motion to an object. The method consists ofproviding a movable object, vibrating the object at a first select frequency along a first line of action and vibrating the object at substantially the same frequency along a second line of action which is transverse to the first. The second vibration must be at a phase which is shifted from the phase of the first vibration such that substantially circular or elliptical orbital motion is imparted to the object.

[0036] The method of this aspect may also consist of sensing the motion of the object with at least one sensor. Furthermore, the vibrations along the first or second lines of action may be controlled by control circuitry conditioning a signal provided by feedback from the sensor. The control circuitry may be employed to maintain the phase shift between the first and second vibrations. The control circuitry may also be employed to control the amplitude of a vibration.

[0037] It is an object of the present invention to provide a design in which a fluid pump, expander or compression mechanism consists of a monolithic structure and one in which the fluid pump, expander or compression mechanism and any necessary mechanical power source are integrated into a single unit. This design has advantages over the prior art, where each pump and compressor design consists of a relatively complex assembly of moving components. Each design taught by the prior art requires some combination ofvalves, vanes, rotating shafts, seals, bearings, bushings, mechanical linkages, or other wearing components. These mechanical assemblies are required to provide mechanical power to the compressing or pumping mechanism and to properly control the flow of fluid through the device.

[0038] The present invention consists of a mechanical design which eliminates many of the aforementioned components. Accordingly, specific advantages of this invention are an apparatus:

[0039] 1. In which the compressing or pumping apparatus is fashioned into a monolithic structure.

[0040] 2. In which the compressing or pumping apparatus and the means to provide power to it are fashioned into a single integrated unit.

[0041] 3. Which contains no valves, vanes, rotating shafts, shaft seals, bearings, bushings, mechanical linkages, or similar mechanical components.

[0042] 4. Which is hermetically sealed without the use of magnetic or any other coupling means between the mechanical power source and the compression mechanism.

[0043] 5. Which possesses improved durability and reliability.

[0044] 6. Which is lightweight and compact.

[0045] 7. In which all of the mechanical components can be fabricated from the same material.

[0046] 8. Which is balanced mechanically, resulting in operation, which is quiet and substantially free from net vibration.

[0047] 9. In which the kinetic energy and potential energy of each moving component remains constant during operation.

[0048] 10. In which the angular momentum of each moving component remains constant during operation.

[0049] 11. Which produces an orbital motion of one or more of its members without the use of rotating shafts or mechanical linkages.

[0050] 12. Which is efficient and compresses gas at near equilibrium conditions.

[0051] 13. In which the wetted surfaces can be coated easily or otherwise treated to provide a continuous and otherwise preferable contact surface, which is suitable for the pumping or compressing of corrosive or otherwise reactive fluids.

[0052] 14. In which the wetted surfaces can be coated easily or otherwise treated to provide a continuous, smooth, and otherwise preferable contact surface, which eliminates or minimizes degradation of biological or other shear-sensitive fluids.

[0053] The present invention can be used with additional components, to form a complete refrigeration device, heat pump, or heat engine. A key benefit of this invention is the ability to use of one or more tube pairs and their corresponding compression mechanisms as means to compress the working gas and one or more tube pairs as means to expand the working gas. Since all tube pairs can be mechanically coupled and can be synchronized in their orbital motion, work generated from the expansion of the working gas in one or more tube pairs can be used to compress the working gas in the other tube pairs. This design and operating configuration allows for the use of working gases which do not possess a positive Joule-Thompson coefficient. This same basic design can be used as a heat pump and as a heat engine.

[0054] Several specific embodiments of this invention have advantages over the prior art in refrigeration and heat engine applications. In particular, embodiments are disclosed which feature a design:

[0055] 1. In which one or more of the cantilevered tube pairs function to compress fluid while one or more of the cantilevered tube pairs function as expanders to recover mechanical energy from fluid.

[0056] 2. In which the fluid-compression and fluid-expansion components are inherently mechanically coupled.

[0057] 3. Which recovers mechanical work or energy from the expanding fluid and uses it to compress the fluid.

[0058] 4. Which does not require the use of gases that possess positive Joule-Thompson coefficients.

[0059] 5. In which the fluid-compression and fluid-expansion mechanisms are mechanically identical and can function in either capacity.

[0060] 6. In which the function of the fluid-compression and fluid-expansion mechanisms can be changed during operation of the device.

[0061] 7. In which the direction in which thermal energy is transferred can be changed during operation without changing the direction of fluid flows.

[0062] 8. In which specific embodiments can function as refrigeration, heat pump, or heat engine devices.

BRIEF DESCRIPTION OF THE DRAWINGS

[0063]FIG. 1 is a cut away view of an orbital fluid pump.

[0064]FIG. 2A is a cross-sectional view of the outer tube and outer lobe of an orbital fluid pumping mechanism.

[0065]FIG. 2B is a cross-sectional view of the inner member and inner lobe of an orbital fluid pumping mechanism.

[0066]FIG. 2C is an assembled view of the inner member, outer tube and inner and outer lobes of an orbital fluid pumping mechanism.

[0067]FIG. 3A is a top cross-sectional view of the outer tube and outer lobe of an orbital fluid pumping mechanism.

[0068]FIG. 3B is a top cross-sectional view of the inner member and inner lobe of an orbital fluid pumping mechanism.

[0069]FIG. 3C is a top cross-sectional assembled view of the outer tube, common inner member and inner and outer lobes of an orbital fluid pumping mechanism.

[0070]FIG. 4A is a side cross-sectional view of the inner and outer lobes of an orbital fluid pumping mechanism showing the seal that forms as the tube and member orbit with respect to each other.

[0071]FIG. 4B is a side cross-sectional view of an orbital fluid pumping mechanism showing the lobes in the static position.

[0072]FIG. 5A is a top cross-sectional view of an orbital fluid pumping mechanism showing the orbital motion of the outer tube with respect to a stationary inner member.

[0073]FIG. 5B is a top cross-sectional view of an orbital fluid pumping mechanism showing the orbital motion of the inner member with respect to the outer tube.

[0074]FIG. 6A is a cross-sectional view of the inner and outer lobes of an orbital fluid pumping mechanism optimized for implementation in embodiments where the inner member and the outer tube are not parallel.

[0075]FIG. 6B is an alternative cross-sectional view of the inner and outer lobes of an orbital fluid pumping mechanism optimized for implementation in embodiments where the inner member and the outer tube are not parallel.

[0076]FIG. 6C is a schematic diagram of the angle formed between the inner member and the outer tube in an orbital fluid pumping mechanism where the tube and member are not operating parallel to each other.

[0077]FIG. 7A is a cross-sectional view of the inner and outer lobes of an orbital fluid pumping mechanism optimized for pumping viscous fluids.

[0078]FIG. 7B is a cross-sectional view of the inner and outer lobes of an alternative orbital fluid pumping mechanism optimized for pumping viscous fluids.

[0079]FIG. 7C is a schematic diagram of an orbiting constriction which forms between the inner member and outer tube of an orbital fluid pumping mechanism optimized for pumping viscous fluids.

[0080]FIG. 8 is a side cross-sectional view of a single lobed embodiment of the orbital fluid pumping mechanism.

[0081]FIG. 9 is a perspective view of an orbital fluid pump featuring mechanical means of imparting orbital motion.

[0082]FIG. 10A is a perspective view of a single cantilevered tube pair embodiment of an orbital fluid pump, with the outer tube shown in a cut away view.

[0083]FIG. 10B is a perspective view of a four tube cantilevered tube pair embodiment of an orbital fluid pump, with the outer tubes and base shown in cut away views.

[0084]FIG. 11A is a schematic diagram of the fluid flow within a single tubed embodiment of an orbital fluid pump.

[0085]FIG. 11B is a schematic diagram of the fluid flow within a single tubed embodiment of an orbital fluid pump featuring inlet and outlet manifolds.

[0086]FIG. 12 is a schematic diagram of the fluid flow within a single tube pair embodiment of an orbital fluid pump featuring a single pass inlet and outlet.

[0087]FIG. 13A is a schematic diagram of the vibrational modes creating orbital motion in a four tube pair embodiment of an orbital fluid pump.

[0088]FIG. 13B is a schematic diagram of the vibrational modes creating orbital motion in a single tube pair embodiment.

[0089]FIG. 14A is a schematic diagram of a orbital fluid pump featuring an outer tube with varying cross-sectional diameter.

[0090]FIG. 14B is a schematic diagram of a orbital fluid pump featuring an outer tube with an alternate varying cross-sectional diameter.

[0091]FIG. 15A is a side and top cross-sectional view of the outer scroll of an orbital fluid pump featuring a scroll pumping apparatus.

[0092]FIG. 15B is a side and top cross-sectional view of the inner scroll of an orbital fluid pump featuring a scroll pumping apparatus.

[0093]FIG. 15C is an assembled side and top cross-sectional view of an orbital fluid pump featuring a scroll pumping apparatus.

[0094]FIG. 16 is a perspective view of an orbital fluid pump featuring two sets of cantilevered tube pairs mounted on opposite sides of a base.

[0095]FIG. 17 is a cut away view of a refrigeration apparatus featuring orbital fluid pumps as compressors and expanders.

[0096]FIG. 18 is a schematic diagram of an apparatus for imparting orbital motion to an object.

[0097]FIG. 19A is a schematic diagram of a velocity sensor.

[0098]FIG. 19B is a schematic diagram of a drive mechanism.

[0099]FIG. 19C is a schematic diagram of a sensor/drive mechanism pair featuring a shared magnet.

[0100]FIG. 19D is a schematic diagram of a sensor/drive mechanism pair featuring a shared coil.

[0101]FIG. 20A is a top cross-sectional view of a single cantilevered tube pair orbital fluid pump showing placement of sensors and drive mechanisms.

[0102]FIG. 20B is a top cross-sectional view of a four cantilevered tube pair orbital fluid pump showing placement of sensors and drive mechanisms.

[0103]FIG. 20C is a side cross-sectional view of a single cantilevered tube pair orbital fluid pump showing placement of sensors and drive mechanisms.

[0104]FIG. 20D is a side cross-sectional view of a four cantilevered tube pair orbital fluid pump showing placement of sensors and drive mechanisms.

[0105]FIG. 21A is a schematic diagram of the control circuit for an apparatus for imparting orbital motion to an object.

[0106]FIG. 21B is a schematic diagram of enhancements to the circuit shown in FIG. 21A making it suitable for controlling the orbital motion of a orbital fluid pump based on four cantilevered tube pairs.

[0107]FIG. 22 is a schematic diagram of the phase shift control portion of a control circuit for controlling the apparatus for imparting orbital motion to an object.

[0108]FIG. 23 is a cut away view of a refrigeration apparatus based on cantilevered tube pairs mounted on opposite sides of a base.

[0109]FIG. 24 is a cut away view of a refrigeration apparatus based on cantilevered tube pairs mounted on opposite sides of a base and featuring heat exchange devices mounted on the free ends of the cantilevered tubes.

[0110]FIG. 25A is a top cut away view of a refrigeration apparatus based upon four pairs of cantilevered tubes showing placement of drive mechanisms and sensors.

[0111]FIG. 25B is a top cut away view of a refrigeration apparatus based upon four cantilevered tube pairs showing an alternative placement of drive mechanisms.

[0112]FIG. 25C is a side cut away view of a refrigeration apparatus based upon two sets of cantilevered tube pairs mounted on opposite sides of a base showing placement of drive mechanisms and sensors.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0113] The present invention consists of several embodiments. The first and preferred embodiment is an orbital fluid pumping mechanism with two lobes. An orbital fluid pumping mechanism with one lobe is also disclosed. A series of embodiments for fluid pumps which may feature the orbital fluid pumping mechanism are also disclosed. A typical orbital fluid pump is shown in FIG. 1. The operation of the orbital fluid pumping mechanism is disclosed in the context of a fluid pump. An orbital expander which can be used in conjunction with an orbital or other compressor to implement the refrigeration cycle is also disclosed. In addition an apparatus and method for imparting orbital motion to an object are disclosed. Finally, several embodiments of refrigeration apparatus featuring the orbital fluid compressing mechanism and expander are disclosed.

[0114] I. Orbital Fluid Pumping Mechanism

[0115] The preferred embodiment of the present invention is an orbital fluid pumping mechanism 10. The orbital fluid pumping mechanism 10 is specifically the fluid driving or compressing portion of a fluid pump or compressor, separate from the associated parts and manifolding which are typically a part of a practical pump or compressor. The orbital fluid pumping mechanism 10 is best illustrated in FIG. 2. The orbital fluid pumping mechanism 10 has an outer tube 12 and an inner member 14 positioned substantially concentrically within the outer tube 12. Substantially concentrically is defined as meaning that the inner member 14 is wholly disposed within the outer tube 12, however it is not critical that the outer tube 12 and the inner member 14 share the same axis. It is important that there be a gap 16 of a select dimension between the inner member 14 and the outer tube 12 such that orbital motion of one of these two elements relative to the other can occur.

[0116] The inner member 14 of the orbital fluid pumping mechanism 10 can be a solid member or a hollow tube of any configuration. Preferably in practical embodiments of an orbital fluid pump the inner member is a hollow tube suitable as a conduit for fluid flow.

[0117] A helical outer lobe 18 is associated with the inner surface 20 of the outer tube 12 and a helical inner lobe 22 is associated with the outer surface 24 of the inner member 14. The inner 22 and outer 18 helical lobes are each continuous solid structures, as is best seen in views A & B of FIG. 3. However as illustrated in FIG. 2, each helical lobe 18, 22 may be configured in multiple continuous helical turns 26 having a select vertical separation 28 between the loops 26. The orbital fluid pumping mechanism 10 may have apparatus associated with the inner member 14 or the outer tube 12 which can cause either the tube 12 or member 14 and its associated lobe to orbit with respect to the other. Suitable apparatus for inducing orbital motion is fully disclosed in Section IV below.

[0118] The lobes 18, 22 of the orbital fluid pumping mechanism 10 can be configured in numerous ways. In a favored embodiment of the orbital fluid pumping mechanism 10, the inner 22 and outer 18 helical lobes are configured such that they contact each other as orbital motion occurs, forming an orbital seal 30. This embodiment is best shown in FIGS. 4 and 5. With this lobe configuration, fluid is pumped by the action of the orbiting seal 30 formed between the adjacent surfaces of the lobes 18, 22 as orbital motion occurs.

[0119] The orbiting seal 30 is best shown in FIG. 4 which represents side views of the relative positions of outer tube 12 and inner member 14. Each view is a cross section of tube 12 member 14 with their corresponding inner and outer lobes 18, 22. The cross section is taken along line X of FIGS. 5A and 5B. View A of FIG. 4 shows the relative positions of lobes 18 and 22 for step 1 of FIGS. 5A and 5B. At this step, the seal 30 is passing through the plane of cross section X and is on the right side of the tube arrangement. The lobe turns 26 on the left side of this cross section are at their maximum displacement from each other. View B of FIG. 4 shows the relative positions of the lobes 18, 22 for step 2 of FIGS. 5A and 5B. At this step, seal 30 is in front of the plane of cross section X and the lobe turns 26 on both sides are at intermediate positions.

[0120] Adjacent lobe turns 26 must cleanly interlock as seal 30 orbits around the mechanism 10 in order for the mechanism 10 to function properly. This requirement may be met by employing lobe 18, 22 cross sections with sides which have a slight taper as shown in FIG. 4. In addition, the adjacent lobes turns 26 must also seal to isolate adjacent or sub-volumes 79 at all points within an orbit. This requires that the tapers be minimal. To meet these requirements, a variety of lobe 18, 22 cross sections may be used. FIG. 4 shows the cross sections of lobes 18, 22 having substantially straight sides with sharp corners. Other cross sections may have sides with rounded corners or the cross sections of the lobes 18, 22 may be defined by continuous curves.

[0121] The design of lobes 18, 22 may also account for the fact that the walls of outer tube 12 and inner member 14 may not remain exactly parallel during operation. This is particularly true if the orbital fluid pumping mechanism 10 is implemented in a cantilevered tube pair based fluid pump 37 or 37′ as described below in Section II. In such an implementation, non-parallel operation will result from orbital movement of the free ends 38 of the tube 12 and member 14, which in this embodiment is an inner tube 14, resulting from a pivoting action of the tubes 12 and 14 about their fixed ends 39. A related effect is that the walls of the tubes do not remain exactly straight as they deflect but may assume a characteristic curvature resulting from the continuously varying bending moment of the tubes along their length.

[0122]FIG. 6 shows variations of the inner lobe 22 design (FIG. 6A) and outer lobe 18 design (FIG. 6B), which account for non-parallel orbital motion between the outer tube 12 and the inner member 14. FIGS. 6A and B show half cross sections of the inner 22 and outer 18 lobes relative to the center line 40 of the inner member 14 and outer tube 12. FIG. 6A shows an outer lobe 18 having lobe turns 26 of constant diameter, resulting in a lobe shape that is characterized by reference line 41, which passes through like reference points on each lobe turn, and is substantially parallel to centerline 40. FIG. 6A also shows an inner lobe 22 having lobe turns 26 of varying diameter, resulting in a lobe shape that is characterized by reference line 42, which passes through like reference points on each lobe turn 26, and forms angle 44 with reference line 41. As applied to fluid pump 37, which is fully described in Section II below, angle 44 may have a preferable value defined by tube length 46 and orbital amplitude 48, as shown in FIG. 6C. FIG. 6B shows an analogous arrangement of inner 22 and outer lobes 18 in which reference line 42, characterizing the inner lobe 22, is substantially parallel to centerline 40. In this representation, reference line 41 which characterizes the outer lobe 18, forms angle 44 with reference line 42. In both cases, reference lines 41 and 42 may be straight, as shown, or may have curvature, indicating that angle 44 varies along the length of the lobe.

[0123]FIGS. 7A and B show alternative designs for inner and outer lobes 22, 18, which may be preferable for pumping liquids. In these lobe embodiments, seal 30, as shown in FIG. 4, does not form or forms in only one of the two displacement volumes 34, 36, which are best seen in FIG. 2. FIG. 7C shows the relative position of inner member 14 and outer tube 12 at four intervals within a single tube/member orbit. During operation of this embodiment of the fluid pumping mechanism 10, a constriction 50 forms and orbits with the same frequency as that of the tube 12 or member 14. Movement of the constriction 50 in an orbital fashion acts on the fluid, causing it to flow also in an orbital fashion. Lobes 18, 22 guide the fluid through successive turns of the mechanism 10.

[0124] Another effect which causes pumping of fluid in the embodiment represented on FIG. 7 relates to acceleration of the fluid within the mechanism 10. As the outer tube 12 and inner member 14 orbit each other, fluid within the volumes between the inner and outer lobes 22 and 18 is accelerated in a direction, which points to the center of the orbit and revolves with the same frequency as the tubes. This acceleration generates pressure gradients within the fluid and density gradients if the fluid is compressible. There must be a net movement of fluid, also in an orbital fashion, to maintain the density gradients. Lobes 18 and 22 guide the fluid through successive turns of the mechanism 10.

[0125] Variation to the above fluid pumping mechanism 10 embodiments may consist in addition of multiple lobes 18 and 22 which are wrapped in a parallel fashion. This would increase the throughput of the mechanism. Multiple compression or pumping mechanisms may also be located within the same tube arrangement to add stages of compression or pumping.

[0126]FIG. 8 shows another aspect of the present invention, which is an apparatus similar to the orbital fluid pumping mechanism 10 described above, but having only one lobe 18 or 22 attached to either the inner surface 20 of the outer tube 12 or the outer surface 24 of the inner member 14. In the single lobe aspect, no seal forms, and fluid is pumped as orbital motion occurs by the action of an orbiting constriction 50, as shown in FIG. 7C, formed between the adjacent surfaces of the lobe and the exterior surface of the inner member or the inner wall of the outer tube. The constriction 50 orbits with the same frequency as that of the tube 12 or member 14. Movement of the constriction 50 in an orbital fashion acts on the fluid, causing it to flow also in an orbital fashion. Lobe 18 or lobe 22 whichever is present, guides the fluid through successive turns of the single lobed orbital fluid pumping mechanism 10.

[0127] The apparatus which is used to impart orbital motion to the orbital fluid pumping mechanism 10 can be of any suitable type including mechanical linkages 51 (FIG. 9) or a electromagnetic drive mechanism 52. A suitable method of imparting and controlling orbital motion and apparatus for imparting orbital motion are disclosed in detail in Section IV below.

[0128] II. Orbital Pump

[0129] An complimentary embodiment of the present invention is an apparatus for pumping fluid 37. In its most fundamental form, as depicted in FIG. 10, the apparatus consists of a base 56 and a cantilevered tube pair 58 attached to the base 56. A cantilevered tube pair 58 consists of two tubes corresponding to the outer tube 12 and inner member 14 of the orbital fluid pumping mechanism 10 described above. A cantilevered tube pair is formed when the inner tube (member) 14 is placed concentrically within the outer tube 12, and both tubes 12 and 14 are attached to the base 56 at a fixed end 39 of each tube 12 and 14, with the other free ends 38 left free to orbit. In addition a pumping mechanism is operatively associated with the inner and outer tubes. The pumping mechanism can be but is not required to be an orbital fluid pumping mechanism 10 as described in Section I above. As shown in FIG. 1, the apparatus for pumping fluid may also have an outer housing 64 which in conjunction with the base 56 forms a support structure 66.

[0130] The orbital pump 37 has an inlet port 68, which connects to and provides flow to an inlet conduit 70, to which connects the inner tube 14. Inlet conduit 70 provides fluid flow to the fixed end 39 of inner tube 14, which flows through the cantilevered tube pair 58 as depicted by arrows, in FIG. 11A, and exits through outlet conduit 72, which connects to outer tube 12. Outlet conduit 72 connects to and provides flow to outlet port 74.

[0131]FIG. 12 shows a similar embodiment where the inlet port 68 is located at the free end 38 of the cantilevered tube pair 58. Fluid flows in the inlet port 68 and out the outlet conduit 72 and outlet port 74 in a single pass.

[0132]FIG. 10 also shows a multiple cantilevered tubed fluid pump embodiment 37′. In this embodiment, inlet port 68 connects to and provides flow to inlet manifold 76, to which connect multiple inner tubes 14. Inlet manifold 76 divides the inlet flow into four essentially equal components. Each flow component enters the fixed end 39 of one of the four inner tubes 14, flows through the cantilevered tube pair 58 as depicted by arrows in FIG. 11B, and recombines with the other flow components in outlet manifold 78, which connects to outer tubes 12. Outlet manifold 78 connects to and provides flow to the outlet port 74.

[0133] Description of Operation of Orbital Pump

[0134] A most favored embodiment of the present invention is an orbital fluid pump with one (embodiment 37) or more (embodiment 37′) cantilevered tube pairs 58 featuring the orbital fluid pumping mechanism 10 of Section I above. The operation of the orbital fluid pumping mechanism 10 and an orbital pump 37 is most conveniently described together.

[0135] Assembled views C in FIGS. 2 and 3 show the arrangement of the outer and inner tubes 12 and 14 and their corresponding lobes 18 and 22 while the tubes are in their static or rest positions. Operation of the pump 37 is based on vibrations of the free ends 38 of outer tube 12 or both outer and inner tubes 12 and 14. For the four tube pair embodiment 37′ shown in FIG. 10, each of the four outer tubes 12 vibrates in two modes, which are perpendicular to each other in space. These two modes of vibration can occur as a result of restoration forces in the tube walls which result from deflections of the free ends 38 of outer tubes 12 about their respective fixed ends 39, or the restoration forces may be actively applied.

[0136] Typically, as the free ends 38 of outer tubes 12 deflect from their static positions, a restoration force is generated within the tube walls, which is in the direction opposite of the deflection and proportional to the magnitude of the deflection. These forces result in vibrations, which are periodic in nature and are generally referred to as simple harmonic motion. Resulting vibrations occur at the fundamental resonant or natural frequency of the tubes 12. This frequency is related to the tube stiffness and bending moment.

[0137] A clear understanding of the vibrations can be obtained from FIG. 13A. The two modes of vibration are presented separately for clarification. For each mode, two top views of the pump 37′ are shown including base 56 and four outer tubes 12. As seen in FIG. 13A, the 1^(st) mode consists of deflections of the free ends 38 of outer tubes 12 along lines Y and Y′. Vibrations are such that while the free ends 38 of the two outer tubes 12 positioned along line Y are moving toward each other, the free ends 38 of the two outer tubes 12 positioned along line Y are moving away from each other and vise versa. This vibrational mode is characterized by requiring that the deflections of the free ends 38 of the tubes 12 along line Y and those along line Y are always phase shifted by 180° with respect to each other. This vibrational mode is further characterized by requiring that the relative velocities of the tubes 12 along line Y and those along line Y are also always phase shifted by 180° with respect to each other. The nature of the 2^(nd) vibrational mode is exactly analogous to the first. In this case, the vibrations are along lines X and X′, as shown in FIG. 13A.

[0138] The vibrational modes of the pump embodiment 37, which contains a single cantilevered tube pair 58, are shown in FIG. 13B. The two modes of vibration are presented separately for clarification. For each mode, two top views of the embodiment are shown including base 56, outer tube 12, and inner tube 14. As seen in FIG. 13B, the 1^(st) mode consists of deflections of the free ends 38 of outer tube 12 and inner tube 14 along line Y. Arrows indicate the direction of movement for the outer tube 12 and the inner tube 14. Vibrations are such that the movements of the free ends 38 of outer tube 12 and inner tube 14 along line Y are in opposition to each other. This vibrational mode is characterized by requiring that the deflections of the free ends 38 of outer tube 12 and inner tube 14 along line Y are phase shifted by 180° with respect to each other. The nature of the 2^(nd) vibrational mode is exactly analogous to the first. In this case, the vibrations are along line X, as shown in FIG. 13B.

[0139] Vibrations of this type occur between pairs of members (tubes in the above embodiments), which vibrate in opposition to each other. This arrangement produces essentially no net forces or torques acting on the base 56 and is preferred for generating stable vibrations. These constraints are met in the design of a tuning fork in which two or more tynes vibrate in opposition to each other in one or more modes. Knowledge of these principles has been used in other useful devices, which require one or more stable vibrational modes. Examples are coriolis flow meters as explained in Smith, U.S. Pat. No. 4,187,721 and Smith, Cage, U.S. Pat. No. 4,491,025 and an angular rate sensor, as explained in Cage, U.S. Pat. No. 5,193,391.

[0140] A further requirement of the present invention is that the vibrational modes described in FIGS. 13A and 13B are phase shifted by 90° in time. As shown in FIGS. 13A and 13B, when this requirement is satisfied, the resulting motion of the free tube ends 38 will be orbital in nature; Each of the free tube ends 38 will orbit around its static or rest position. The rate of revolution will be equal to the resonant frequency of the two vibrational modes and the radius of revolution will be equal to the amplitude of the two vibrational modes.

[0141] Proper design of an orbital pump 37 or 37′ requires that specific attention be paid to the natural or resonant frequencies of the inner 14 and outer 12 tubes. For the four tube pair embodiment 37′ shown in FIG. 10, inner tube 14 must remain substantially static or stationary during operation. This condition requires that the fundamental natural or resonant frequencies of inner tube 14 and outer tube 12 be substantially different. Consideration must also be given to the higher ordered resonant frequencies of both tubes 12 and 14 to generate a design in which there is substantially no match between any of the likely resonant frequencies of inner tube 14 with those of outer tube 12.

[0142] For the single tube pair embodiment 37 shown in FIG. 10, inner tube 14 and outer tube 12 both orbit about their static positions. This condition requires that the fundamental natural or resonant frequencies of inner tube 14 and outer tube 12 be substantially the same. An additional requirement for this embodiment is that any of the likely natural or resonant frequencies of outer housing 64 or base 56 or their combination, which forms support structure 66, as shown in FIG. 1, be substantially different from the fundamental resonant frequencies of inner tube 14 and outer tube 12 for this embodiment.

[0143] To accomplish these requirements, proper design of any embodiment must include consideration of the tube characteristics, which determine the fundamental resonant frequencies of inner tube 14, outer tube 12, and support structure 66. For each tube, these characteristics include material of fabrication, length, diameter, wall thickness, cross-sectional shape, and masses added to the tube and their positions along the tube length.

[0144] Practical methods for matching the tube frequencies of inner 14 and outer 12 tubes include procedures in which two tubes, having substantially the same mechanical characteristics as described above, are mounted to a common test base, side by side in cantilevered fashion, and are vibrated in one or more modes, using the means described in Section IV or other appropriate means, and the fundamental natural or resonant frequency of the tubes is determined from the resulting vibration. Alternatively, one tube having substantially the characteristics of a preferred inner tube 14, and another having substantially the characteristics of a preferred outer tube 12, are mounted to a common test base in a concentric and cantilevered fashion, and the mechanical characteristics of one or both tubes are varied until a stable, sustainable, vibration is obtained in one or more modes and at a suitable amplitude. Then the fundamental natural or resonant frequency or higher resonant frequencies of the tubes can be determined from the vibration.

[0145] The orbital motion of the free tube ends 38 results in a relative orbital motion of the lobes 18, 22 within a tube pair 58. This action is illustrated in FIGS. 5A and 5B. Designations in FIGS. 5A and 5B correspond to those of the assembled view C in FIG. 3. FIGS. 5A and 5B show the top view of the outer 12 and inner 14 tube arrangement at four times within a single orbit. FIG. 5A shows the movement of outer tube 12 about a static inner tube 14. This movement applies to the four tube pair embodiment 37′. FIG. 5B shows the movement of both outer tube 12 and inner tube 14 about their static positions. This movement applies to the one tube pair embodiment 37.

[0146] As the free ends 38 of one or both outer and inner tubes 12 and 14 orbit, seal 30 is made between all of the adjacent lobe turns 18 and 22. The seal 30 orbits with the same frequency as those of the tubes 12, 14. Seal 30 isolates a series of sub-volumes 79 within volumes 34 and volumes 36. With each orbit, fluid within the enclosed and free end 38 of outer tube 12 is trapped within the top sub volume 79 of volumes 34 and 36. A minimum of one complete turn for each of lobes 18 & 22 is required for the mechanism 10 to function properly. This ensures that the mechanism will isolate fluid in at least one sub-volume 79 of volumes 34 and 36 from the free end 38 of outer tube 12 before sub-volume 79 of volumes 34, 36 opens to the exit volume 80 at the opposite end of the mechanism 10. Preferably, multiple lobe turns 26 may be employed to minimize backflow or leakage of fluid back through the mechanism 10. With each orbit, the trapped fluid sub-volumes 79 are transferred to the next lower respective sub-volume 79 until they are expelled from the last sub-volume 79 at the opposite end of the mechanism 10. This action compresses and/or pumps fluid from inner tube 14, through the orbital fluid pumping mechanism 10, and into outer tube 12 to its fixed end 39. Compressing or pumping in the opposite direction is achieved when direction of the orbits is reversed.

[0147] Alternative Embodiments of Orbital Pump

[0148] Alternative embodiments for orbital pumps 37 and 37′ may include cantilevered tube pairs 58 in which the diameters of inner tube 14 or outer tube 12 or both vary along their lengths. Examples of varied diameter pumps 82 are shown in FIGS. 14A and B. FIG. 14A shows a cantilevered tube pair 58 in which outer tube 12 consists of two sections having different diameters. Specifically, the diameter of the section of outer tube 12 that is near its free end 38 is larger than the diameter of the section that is near its fixed end 39. This variation allows for independent design of the outer tube 12 orbital frequency and orbital fluid pump mechanism 10 displacement volume. The transition from one diameter to the other may occur at any point along the length of outer tube 2. FIG. 14B shows another variation in which the diameter of outer tube 12 varies continuously along a section of its length and has a constant diameter along another section of length. Either or both outer tube 12 or inner tube 14 may have these variations. Other characteristics, which can be varied, include tube wall thickness and cross-sectional shape. Alternative embodiments may also include arrangements in which the mounting location of the fixed end 39 of inner tube 14 is substantially the same as that of outer tube 12.

[0149] Another alternative embodiment of an orbital pump is the use of a scroll compression mechanism as the pumping apparatus instead of the orbital fluid pumping mechanism 10 described above. Scroll mechanisms rely on the relative orbital motion between two inter-positioned scrolls 83. An embodiment of the orbital fluid pump 37 with a scroll compression mechanism is shown in FIG. 15. Scroll 84 is attached via base 86 to the free end of inner tube 14 as shown in FIG. 15A. Base 86 includes port 88 for allowing fluid to flow from the scroll compression mechanism into inner tube 14. The second scroll 90 is attached to the free end 38 of outer tube 12 as shown in FIG. 14B which shows outer tube 12 having a flat end 92, which provides a seal 94 between the displacement volumes that form during operation. FIG. 15C shows inner and outer tubes 14, 12 with scrolls 84, 90 in their static positions. FIG. 15C shows gap 96, which forms between base 86 and the wall of outer tube 12. Embodiments may include combinations of flat and rounded ends. Arrows show the direction of flow in tubes 12, 14.

[0150] The relative motion of the scrolls is analogous to that of the lobes as shown in FIG. 5B. As outer tube 12 and inner tube 14 orbit, fluid from the outer tube 12 flows into the scroll mechanism via gap 96 between the inner tube base 86 and the wall of outer tube 12. Fluid is trapped within volumes which are created by seals formed by contact of the two scrolls at various points and compressed as the two scrolls orbit each other. The fluid within the trapped volumes exits the mechanism through port 88 in base 86 and flows into inner tube 14.

[0151] Scrolls for the embodiments of the present invention based on cantilevered tubes must possess a feature which accounts for the pivotal nature of cantilevered orbital motion. In essence, the orbital amplitude of this or any compression mechanism varies along the length of the compression mechanism. To account for this behavior, one scroll 84, or both, 84 and 90 must possess a taper along its length (similar to that previously described for the lobed mechanism). This taper can be characterized using a circle involute as a cross section of the scroll. Mathematically, the coordinates of the curve which forms a circle involute are given by:

x=a(cos t+t sin t)

y=a(sin t−t cos t)

[0152] where x, y are the coordinates of the curve, a is the radius of the circle, and t is a parameter relating to arc length along the circle. A 3-dimensional scroll 84 and 90 will have a characteristic cross section described by these equations. For a scroll 84 or 90 with no taper, the cross section will be constant along the principle axis of the scroll. For a scroll 84 or 90 having taper, the cross section will vary along the principle axis of the scroll 84 or 90. This variation can be described, mathematically, as a variation of the radius of the circle a, which describes each cross section. The variation of the radius of the circle a along the length of a tapered scroll may be linear or nonlinear. The variation of the radius of the circle a may occur in each scroll 84 and 90 or only one.

[0153] In addition to changing the pumping mechanism associated with the cantilevered tube pairs 58, the position and orientation of the tube pairs 58 can be changed. FIG. 16 shows a variation of the positions and orientations of the four cantilevered tube pairs 58 in which the four tube pairs 58 are arranged as two sets mounted on opposing faces of base 56. Another embodiment not shown on a figure consists of the four pairs 58, which are oriented in a radial fashion from a central base 56. Many variations can be obtained including those featuring other numbers of cantilevered tube pairs 56.

[0154] There are numerous variations of base 56 with manifold variations which could allow flow to proceed through the cantilevered tube pairs in series instead of in parallel as in the embodiments described above. Flow can be reversed to flow through the outer tubes 12 first and back through the inner tubes 14. A manifold arrangement could be designed for pumping two separate flows as in an artificial heart. In that case, the manifolding would need to be streamlined to prevent stagnant flow locations within the manifolding. Locating ports along tangents to the manifold would prevent stagnant flow locations.

[0155] Another aspect of the present invention is also an apparatus for pumping fluid similar to that described above, but not based upon a cantilevered tube pair. In this aspect, the apparatus consists of an outer tube, an inner tube positioned substantially concentrically within the outer tube, a pumping mechanism associated with one or both of the inner and outer tubes and an apparatus designed to impart orbital motion to one or both tubes, forming an orbiting tube. An apparatus for pumping fluid which is not based upon a cantilevered tube can be constructed where both ends of the tube pair are fixed and orbital motion occurs around a flexible center of the tube pair. Alternatively, both ends of the tubes comprising the tube pair can be mounted such that they are free to orbit with respect to each other. In any embodiment, the pumping mechanism associated with the non-cantilevered tube pair can be the orbital fluid pumping mechanism 10 described above or another suitable pumping mechanism which operates based upon orbital motion. A suitable apparatus for imparting orbital motion is fully disclosed in Section IV below.

[0156] III. Orbital Expander

[0157] Another aspect of the present invention is an orbital apparatus for recovering energy from a fluid stream. This type of apparatus is commonly known as an expander 97. The expander of the present invention consists of an outer tube 12 and an inner member 14 concentrically positioned within the outer tube 12 such that an annular space 98 is located between the outer tube 12 and the inner member 14. A representative expander is shown in FIG. 17 along side a compressor based upon an orbital pump 37 as described above. A fluid stream inlet 100 opens into the annular space 98, and a fluid stream outlet 102 leads from the annular space 98. In addition a helical outer lobe 18 is associated with the inner surface 20 of the outer tube 12, and a helical inner lobe 22 is associated with the outer surface 24 of the inner member 14 and further associated with the helical outer lobe 18. Each lobe 18, 22 is located in fluid communication with a fluid stream flowing between the fluid stream inlet 100, and the fluid stream outlet 102.

[0158] The inner 22 and outer 28 helical lobes may be configured such that a flow of fluid introduced at the inlet 100 and flowing to the outlet 102 will cause orbital motion in at least one of the inner member 14 or the outer tube 12.

[0159] The expander 97 aspect of this invention may have apparatus attached for recovering the energy from the orbital motion caused by the fluid flow. The apparatus for recovering energy may consist of a mechanical linkage, a generator which contains the same components as an electromagnetic drive mechanism 52, or other suitable device. As discussed in detail below in Section V, the orbital expander 97 may be operatively associated with a corresponding fluid pump 37 or 37′ as described above to form the components of a refrigeration apparatus 110 or heat engine.

[0160] IV. Apparatus and Method For Imparting Orbital Motion.

[0161] Another aspect of the present invention is an apparatus 112 and method for imparting orbital motion to any object 114. The apparatus 112 consists of a mechanism for applying two linear periodic forces 116 and 118 to the object 114 along first and second transverse lines of action 120 and 122. The linear forces 116 and 118 and the direction of the lines of action 120 and 122 are best seen in FIG. 18. The linear periodic forces 116 and 118 are applied at substantially the same frequency, but phase shifted with respect to time such that the combined forces serve to drive the object 114 in a substantially circular or elliptical orbit. In addition, two periodic restorative forces 124 and 126 may be applied to the object 114 along the first 120 and second 122 lines of action. The restorative forces 124 and 126 may be actively applied, or may be passive recoil forces caused by the elastic deformation of the object 114 by the first 116 and second 118 periodic linear forces.

[0162] The mechanism for applying the first 116 and second 118 linear periodic forces or the first 124 and second 126 restorative forces may be an electromagnetic drive mechanism 52, a mechanical linkage 51 or other suitable source of an applied force. In addition at least one sensor 128 may be associated with the object 114 to generate a feedback signal 130 from the object 114 relative to the orbital motion. The apparatus 112 may also include a control circuit 132 which can process the feedback signal 130 from the sensor 128 to create a drive signal 134 for the drive mechanism 52. The drive signal 134 may be provided to the drive mechanism 52 as a current which is continuously variable in a periodic fashion with respect to time, or the drive signal 134 maybe provided to the drive mechanism 52 as a plurality of pulsed currents 128.

[0163]FIG. 19 is a schematic representation of a sensor and drive mechanism 52 which are suitable for implementation of the present invention.

[0164]FIG. 19A shows velocity sensor 128, which consists of magnet 136 and solenoid 138. Magnet 136 and solenoid 138 are mounted to outer tubes 12, inner tube 14, or to a stationary housing 64. FIG. 19B also shows electromagnetic drive 52, which consists of magnet 140 and solenoid 142. Magnet 140 and solenoid 142 are mounted to outer tubes 12, inner tube 14, or to a stationary housing 64. FIG. 19 also shows variations C and D, which are practical arrangements for both the velocity sensor 128 and electromagnetic drive 52.

[0165]FIGS. 20A and 20C shows the arrangement and location of velocity sensor 128 and electromagnetic drive 52 components in the single cantilevered tube pair pump embodiment 37. Magnets 136, 140 can be mounted to outer tube 12 and can be located in planes X or Z as shown in FIG. 20A. Solenoids 138, 142 can be mounted to stationary housing 64 and can be located in planes X or Z as shown in FIGS. 20A and 20C. The positioning of these components can be reversed. The velocity sensor 128 and electromagnetic drive mechanism 52 can be mounted at any suitable location along the lengths or ends of outer tube 14 and housing 64.

[0166]FIGS. 20B and 20D shows the arrangement and location of velocity sensor 128 and electromagnetic drive mechanism 52 in the four tube pair pump embodiment 37′. Again, magnets 136, 140 can be mounted to outer tubes 12 and can be located in planes X or Z as shown in FIG. 20B. Solenoids 138, 142 can also be mounted to outer tubes 12 and can be located in planes X or Z as shown in FIGS. 20B and 20D. Alternatively the positioning of these components can be reversed. Velocity sensor 128 and electromagnetic drive mechanism 52 can be mounted at any suitable location along the lengths or ends of outer tubes 12.

[0167]FIG. 21A schematically represents the velocity sensors 128, electromagnetic drives 52, and corresponding electrical circuit 132 for the one tube pair pump embodiment 37. The circuit 132 includes amplifiers 144 a and 144 b, integrators 146 a and 146 b, and filters 148 a and 148 b to condition the feedback signals 130 a and 130 b generated by sensors 128. The outputs of filters 148 a and 148 b are referred to as the conditioned velocity signals 150 below. The circuit 132 provides peak detectors 152 a and 152 b to measure the maximum value of the conditioned velocity signals 150 a and 150 b over a period of time that is significantly greater than the period of vibration. The circuit 132 provides instrumentation amplifiers 154 a and 154 b to compare the maximum conditioned velocity signal 150 to reference voltage 155 and to generate a signal that is proportional to the difference between these inputs. The circuit 132 provides integrators 156 a and 156 b to integrate the difference signal in time and potentiometers 158 a and 158 b to provide a linear combination of the difference signal and integrated difference signal, now referred to as the control signals 160 a and 160 b, to multipliers 162 a and 162 b.

[0168] The circuit provides first and second phase shifters 164 and 166 to phase shift the conditioned velocity signal 150 a by a desired quantity so as to synchronize the drive signals 134 a and 134 b in a manner to produce the desired vibrational behavior. The multipliers 162 a and 162 b multiply the phase-shifted signals 165 a and 167 b with corresponding control signals 160 a and 160 b and create a negative feedback to produce drive signals 134 a and 134 b to control the amplitude of the measured conditioned velocity signals 150 a and 150 b to a specified value. The circuit 132 provides inverters 168 a and 168 b to invert the drive signals 134 a and 134 b (phase shift the signals 180°) and thus creating two additional drive signals 134 c and 134 d for a total of four drive signals 134 a-d, one for each electromagnetic drive 52. The circuit 132 provides for current gain with current gain amplifiers 170 a-d to generate current gain in each of the four drive signals 134 a-d.

[0169]FIG. 21B shows an arrangement of velocity sensors 128 and electromagnetic drives 52 suitable for controlling and imparting orbital motion to the four tube pair pump embodiment 37′ for use with the circuit 132 of FIG. 21A.

[0170] Operation of Control for Apparatus for Imparting Orbital Motion

[0171] Operation of a sensor 128 comprising a combination of magnets 136 and solenoids 138, as shown in FIG. 19, generates a voltage across the solenoid leads 172 that is proportional to the rate of change of magnetic flux within the enclosed area of the turns, which comprise the solenoid 138. If the variation of magnetic flux with distance from magnet 136 along its axis is approximately linear (within the range of movement of the solenoid 138), then the induced voltage across the solenoid 138 will be proportional to the relative velocity between magnet 136 and solenoid 138. This induced voltage can be used as a measure of the relative velocity between the free ends of two adjacent outer tubes 12, the free ends 38 of an outer 12 and inner tube 14, or between the free end 38 of an outer tube 12 and a fixed reference point, located on a housing 64. In any case, one member contains a magnet 136 and the other member contains a solenoid 138.

[0172] Accurate measurement of the relative velocity resulting from one of the vibrational modes requires that the velocity sensor 128 or combination of sensors 128 used for that mode is substantially insensitive to the relative velocities generated by the other vibrational mode. To meet this requirement, a combination of sensors 128 is used to measure the relative velocities of each vibrational mode. Referring to FIG. 21A, sensors 128 a and 128 b are used to measure the relative velocity between outer tube 12 and housing 64 and resulting from vibrations along line Y. The configurations of magnets 136 and solenoids 138, which comprise sensors 128 a and 128 b, are such that movement of the outer tube 12 in one direction along line Y generates a positive voltage in both sensors 128 a and 128 b and movement in the opposite direction generates a negative voltage in sensors 128 a and 128 b. For this configuration, the sum of signals 130 a from sensors 128 a and 128 b will produce the desired signal for measuring velocities for vibrational modes along line Y. Any vibrations along line X will result in signals being produced in sensors 128 a and 128 b that are substantially of the same magnitude but of opposite sign. Thus, when these two signals are summed as described, the signal components that result from movement along line X will cancel. A configuration of this nature for both sensor pairs 128 a-d will result in velocity signals 130 a and 130 b which are proportional only to the velocities generated by the corresponding vibrational mode.

[0173] Velocity signals from sensor pairs 128 a-b and 128 c-d are amplified, integrated, and filtered as shown in FIG. 21A. The order in which signals are amplified, integrated, and filtered can be varied. Signal integration is required because the maximum vibrational amplitude or travel should be controlled rather than the maximum velocity. Controlling the maximum amplitude is preferred because this ensures that seal 30 forms properly as the lobes 18 and 22 orbit. Measuring and controlling the maximum velocity will not ensure this condition because the maximum velocity and maximum amplitude are not uniquely related as the vibrational or orbital frequency varies. Measuring the maximum amplitude is accomplished by integrating the velocity signal with respect to time. This technique is known to those skilled in the art and can be accomplished by a variety of means. Specific means is described in Smith, U.S. Pat. No. 4,422,338. Negative feedback of the substantially DC component of the integrated signal ensures that the integrated signal does not saturate due to small DC components in the velocity signal.

[0174] Peak detectors 152 a and 152 b measure the maximum value of the conditioned velocity signals 150 a and 150 b over a time substantially greater than the period of vibration. The maximum signals are compared to reference voltage 155 using instrumental amplifiers 154 a and 154 b. The outputs are proportional to the differences of the two inputs.

[0175] Integrators 156 a and 156 b integrate the difference signals with respect to time and potentiometers 158 a and 158 b provide linear combinations of the difference signals and integrated difference signals to multipliers 162 a and 162 b. The control signals 160 a and 160 b provide negative feedback to the drive signals 134 a and 134 b and regulate the amplitude of the corresponding vibration. Those skilled in the art will recognize this control means as a proportional/integral feedback mode. Other feedback modes, which can be used for this purpose include but are not limited to proportional and proportional/integral/derivative.

[0176] The conditioned velocity signal 150 a from sensors 128 a and 128 b is phase shifted using phase shifters 164 and 166 and is fed (in a positive feedback sense) to multipliers 162 a and 162 b along with the control signals 160 a and 160 b from potentiometers 158 a and 158 b. The product of these two signals provides drive signals 134 a and 134 b to drive mechanisms 52 a and 52 b. Inverter 168 a and 168 b phase shift the drive signals 134 a and 134 b from multipliers 162 a and 162 b by 180°. The resulting signals provide the waveforms to drive mechanisms 52 c and 52 d. All of the waveforms the drive mechanisms 52 a-d acquire current using the current gain amplifier 170 a-d as shown. This provides electrical power to the drives 52 a-d having an amplitude, frequency and phase needed to maintain the desired vibrational mode.

[0177] Phase shifting of the conditioned velocity signal 150 a from sensors 128 a and 128 b is required to compensate for phase shifts in the circuit 132 due to the inherent behavior of active circuit components and also to compensate for drive solenoid 142 induction. This phase shift is accomplished by phase shifter 164. Phase shifting is also required for drives 52 b and 52 d. This is accomplished using phase shifter 166. The input to phase shifter 166 can be the conditioned velocity signal 150 a from low-pass filter 148 a, as shown, or the output 165 of phase shifter 164.

[0178] The electromagnetic drives 52 each consist of a magnet 140 and solenoid 142. Orientation of magnet 140 and solenoid 142 as shown in FIG. 21A is such that the magnetic flux lines from magnet 140 intersect the solenoid 142 turns in a manner so that a large component of the magnetic flux is perpendicular to both the tangent of a solenoid turn and the line of relative motion between the magnet 140 and solenoid 142. This arrangement results in the maximum force generated along the line of relative motion. The magnitude of this force varies with the current through the solenoid 142, providing a time-varying force which maintains the desired vibration.

[0179] The vibrational modes for the embodiments described herein should preferably consist exclusively of the fundamental resonant vibrational mode for the tubes 12 and 14. Other vibrational modes are possible and may be discouraged by the appropriate placement of the velocity sensors 128 and electromagnetic drives 52 onto the outer tubes 12 and/or housing 64. All components should be located in a manner, which eliminates or minimizes any extraneous feedback signals from the velocity sensors 128, through the circuit 132, and to the electromagnetic drives 52, which can create or promote any vibrational modes other than the fundamental resonant mode.

[0180] The design and location of the velocity sensor 128 and electromagnetic drive 52 components may be such that they minimize or eliminate any torsional moments or torques on the vibrating tubes 12, 14. This will result in a vibrational mode in which the movement of the vibrating members (within each mode) is translational only as is preferred.

[0181] Variations to the Circuit, Sensors, and Drives

[0182] The phase shift produced by an active circuit component will vary with the vibrational frequency of the input signal. This input frequency is the frequency of the two vibrational modes and does vary with the temperature of the tubes 12 and 14 and the temperature, pressure, and density of the fluid contained within the tubes 12 and 14. As a result, the phase shift of an active circuit component will generally drift over time with operation, resulting in an orbital motion, which is not always circular. The required phase shift of phase shifter means 166 may also vary with orbital amplitude. To address these issues, the phase shift in time between the conditioned velocity signals 150 a and 150 b from the two vibrational modes may be controlled by a feedback controller 174 as shown in FIG. 22.

[0183] Control of the phase shift in time can be accomplished by generating a signal that is proportional to the cosine of the phase shift angle between the two vibrational signals. This is accomplished by providing the two conditioned velocity signals 150 a and 150 b to analog multiplier 176. The output of analog multiplier 176 is filtered using low (DC) pass filter 178. The output of filter 178 is the substantially DC component of the two-signal product and will have a value of zero for a 90° phase shift between the input signals, will be positive for phase shifts <90°, and negative for a phase shifts >90°. This signal is fed to phase shift control 180 to regulate the phase shift to substantially 90°.

[0184] Phase shift control 180 may operate in a variety of ways. One approach is to generate an output waveform that is a linear combination of the conditioned input signal 150 a and a second signal, which is signal 150 a phase shifted by an amount >90°. The signal from low (DC) pass filter 178 is used to determine the coefficient for weighting of one or both input signal components such that the signal from filter 178 controls the phase shift to 90°.

[0185] The circuit presented in FIG. 21A is just one of many variations, which could provide the proper signal processing and waveform generation for the proper operation of the present invention. The circuit in FIG. 21A is an analog type in which signals, within the circuit vary in a continuous fashion. Another method is to employ digital circuitry in which signals possess only discrete values. This could be done using microprocessor technology.

[0186] Another variation relates to the means used to provide current to the electromagnetic drives 52. In the analog circuit as described above, current is provided to the drives 52 in a continuously varying, periodic fashion. Another method for providing current to the electromagnetic drives 52 is to provide it in a pulsed manner. In this approach, control is achieved by varying the duration of time that a substantially constant current flows during each pulse. This approach may be more efficient because the circuit component, which controls the flow of current to the drive 52, is either full-on or off. In either state, power dissipation through the component is minimal.

[0187] There are many possible variations of the configuration and construction of the velocity sensors and electromagnetic drives described herein. A means to shield the sensor solenoid from interfering electromagnetic radiation could be included in any embodiment. Other variations have been developed for other purposes including use in coriolis flow meters as described in Smith, U.S. Pat. No. 4,422,338 and are familiar to those skilled in the art. In general, sensors, which sense position, velocity, or acceleration, may be used.

[0188] V. Embodiments Relating to Refrigeration Apparatus, Heat Pumps, and Heat Engines

[0189] Embodiments based upon an orbital fluid pump 37 or 37′, in which one or more of the cantilevered tube pairs 58 function as compressors 182 while the others function as expanders 97 are applicable to refrigeration and related applications. In these embodiments, the compression and expansion functions are coupled with appropriate heat exchangers to create a complete refrigeration cycle. Operation of the cycle in reverse constitutes a heat engine in which thermal energy is supplied to the cycle and mechanical energy is produced by the cycle. Embodiments, which function in this manner, may contain any number of cantilevered tube pairs 58 and may consist of embodiments where only the outer tubes 12 vibrate as in the four tube pair embodiment 37′ or in embodiments where both inner 14 and outer tubes 12 vibrate, as in the single tube pair embodiment 37.

[0190] A representation of a four tube pair embodiment, useful in refrigeration and related applications is provided in FIG. 17. The refrigeration apparatus 110 consists of base 56 with appropriate manifolding 184 and heat exchange apparatus 186 and 188 to direct the flow of gas and thermal energy in the desired manner. The design consists of four cantilevered tube pairs 58, each consisting of an outer tube 12, inner tube 14, and having corresponding lobes 18, 22 of a fluid pumping mechanism as described previously. In this embodiment, two of the four tube pairs function as gas compressors 182 while the other two function as gas expanders 97. The design also features appropriate velocity sensors 128 and electromagnetic drives 52 as described in detail in Section IV above.

[0191] Base 56, inner tubes 14, and outer tubes 12 may contain insulation 190 to prevent or minimize heat transfer across the boundary of the device or between gas flows. Base 56 also contains heat transfer apparatus 186 between gas flows and heat transfer apparatus 188 across the device boundaries.

[0192] Referring to FIG. 17, the left tube pairs function as compressors 182 that operate on the same principles as the orbital fluid pump 37 described previously. Gas flows from inner tube 14 into the free end of outer tube 12 and into lobes 18, 22 of the fluid pumping mechanism 10. The mechanism 10 performs mechanical work on the gas, compressing it as it exits into outer tube 12 as shown. Thermal energy or heat is transferred from the compressed gas across the device boundary (rejected heat 192) using heat transfer means 188. The compressed gas then flows through heat transfer means 186 in which thermal energy is transferred from the compressed gas to the expanded gas on the opposite side of heat transfer means 186. The compressed gas then flows into the inner tubes 14 of the two expander cantilevered tube pairs 58, into the free ends 38 of outer tubes 12, and through lobes 18 and 22 of the expanders 97. Mechanical work or energy is recovered from the gas as it passes through the expanders 97.

[0193] The gas cools as it passes through lobes 18 and 22 of the expanders 97 and back to the base 56 where thermal energy is transferred across the device boundary (absorbed heat 194) to the gas using heat transfer means 188. The gas then passes into heat transfer apparatus 186 where it cools the compressed gas on the opposite side of heat transfer apparatus 186. From there, it returns to the left cantilevered tube pairs 58, which function as compressors 97.

[0194] The mechanical design and function of lobes 18 and 22 of the expanders 97 are identical to lobes 18 and 22 of a compression mechanism 182. Either set of cantilevered tube pairs 58 can function as compressors 182 or expanders 97. At any given time, the mechanisms that are performing mechanical work on the gas are functioning as compressors 182 and the mechanisms that are recovering mechanical work from the gas are functioning as expanders 97. Because of this feature, the device can perform as a heat pump and can transfer thermal energy in either direction. The direction of transfer can be changed by simply changing the set of cantilevered tube pairs 58, which are performing mechanical work on the gas.

[0195] The set of cantilevered tube pairs 58, which are functioning as expanders 97, may use electromagnetic drives 52 as generators to recover mechanical energy from the expanding gas and convert it to electrical energy. With the appropriate circuitry, this energy can be provided to the electromagnetic drives 52 of the set of tube pairs which are functioning as compressors 182, increasing overall system efficiency.

[0196]FIG. 23 shows a heat pump/refrigeration embodiment in which the two sets of tube pairs 58 are positioned in opposition to each other. All of the functions and designations in the embodiment shown in FIG. 23 are the same as those shown in the embodiment of FIG. 17. FIG. 23 shows the direction of fluid flow through heat transfer means 186 and fluid flow through the shell side by arrows 198 and fluid flow through the tube side by arrows 200.

[0197] For all refrigeration system embodiments, a large variety of designs, locations, and orientations for heat transfer means 186 and 188 can be employed. These designs are well-established and known in the field of heat transfer.

[0198]FIG. 24 shows a variation of the embodiment shown in FIG. 23 and the features shown on FIG. 24 can be applied to the embodiment shown in FIG. 17. The embodiment shown in FIG. 24 has heat transfer means 188 for rejecting heat 192 and absorbing heat 194 located on the free ends 38 of outer tubes 12 of each of the four tube pairs 58. Vibration of outer tubes 12 during operation enhances the rate of heat transfer by heat exchanger 188. The embodiment of FIG. 24 also includes heat transfer means 186 located between the outside of inner tubes 14 and the inside of outer tubes 12 for each of the four tube pairs 58 in place of insulation 190 as was shown in FIG. 23.

[0199]FIG. 25A shows the top view of FIG. 17 with specific attention paid to the arrangement and position of the sensor and drive magnets and solenoids, 136, 138, 140 and 142. FIG. 25A shows an arrangement in which each tube pair 12 and 14 has its own electromagnetic drive pair for each vibrational mode. Magnets 136, 140 are attached to the corresponding outer tubes 12 and solenoids 138, 142 are attached to a housing 64. In FIG. 25B, the solenoids 138 and 142 are attached to a centrally located support 202.

[0200]FIG. 25C shows the end view of the embodiments presented in FIGS. 23 and 24. Location of sensor and drive components 136, 138, 140 and 142 for the vibrational mode that occurs in the plane formed by the two tube pairs 58 is between the two tube pairs 58 as shown on FIG. 25C. Location of sensor and drive components 136, 138, 140 and 142 for the vibrational mode that occurs in the plane perpendicular to the plane formed by the two tube pairs 58 is between each tube pair and an immobile support 204.

[0201] For any of the embodiments described herein, it may be possible that mechanical energy need be provided only to one of the two vibrational modes. Expansion of the gas through the expanders may provide enough mechanical energy to the mechanism to sustain the 2^(nd) vibrational mode without the need to provide electrical energy to actuate that mode.

[0202] For any of the embodiments described herein, there may be a need to match the natural frequencies of the two cantilevered tube pairs 58, which are functioning as compressors 182 and the two cantilevered tube pairs 58, which are functioning as expanders 97. This is due to the fact that the two cantilevered tube pairs 58, which are operating as expanders 97 will most likely be at a lower temperature than those which are operating as compressors 192. This temperature difference will result in a difference in the natural vibrational frequency of the two sets of cantilevered tube pairs 58. The dimensions of the outer tubes 12 can be varied to compensate for the temperature difference. Additional mass can be added to the outer tubes 12 with the higher vibrational frequency. Location of the mass along the length of the outer tubes 12 can be adjusted to vary the natural frequency of those tubes 12.

[0203] Another approach to address this issue is to provide a combination of insulation 190 and/or heat transfer means 186 and/or 188 to the inside and/or outside of the inner 14 and/or outer tubes 12, preferably to the tube surfaces at or near the pivot points, to promote or inhibit heat transfer in a manner, which substantially equalizes the temperatures of all the vibrating outer tubes. 

1. An orbital fluid pumping mechanism, comprising: a. an outer tube having an inner surface; b. an inner member positioned substantially concentrically within the outer tube, the inner member having an outer surface; c. a helical outer lobe operatively associated with the inner surface of the outer tube; and d. a helical inner lobe operatively associated with the outer surface of the inner member, in operative association with the helical outer lobe.
 2. The orbital fluid pumping mechanism of claim 1, further comprising means for orbiting one of the inner member and the outer tube relative to the other.
 3. The orbital fluid pumping mechanism of claim 1 wherein the helical outer lobe and the helical inner lobe are configured to cooperatively define an orbiting constriction between adjacent surfaces of the lobes when the orbiting means is actuated, the orbiting constriction enabling pumping of a fluid.
 4. The orbital fluid pumping mechanism of claim 1, wherein the helical outer lobe and the helical inner lobe are configured to cooperatively define an orbiting seal between adjacent surfaces of the lobes when the orbiting means is actuated, the orbiting seal enabling pumping of a fluid.
 5. The orbital fluid pumping mechanism of claim 1 wherein the means for orbiting one of the inner member and outer tube comprises; means for applying a first periodic force at a select frequency to one of the inner member and outer tube along a first line of action; and means for applying a second periodic force to one of the inner member and outer tube at the select frequency, at a select phase shift from the first linear periodic force, along a second line of action which is transverse to the first line of action.
 6. The orbital fluid pumping mechanism of claim 5 further comprising; means for applying a first periodic restorative force at the select frequency to one of the inner member and outer tube along the first line of action; and means for applying a second periodic restorative force at the select frequency to one of the inner member and outer tube along the second line of action.
 7. The orbital fluid pumping mechanism of claim 6 wherein the second line of action is substantially orthogonal to the first line of action.
 8. The orbital fluid pumping mechanism of 6 wherein the means for applying one of the first and second periodic forces and the first and second periodic restorative forces comprises an electromagnetic drive mechanism.
 9. The orbital fluid pumping mechanism of claim 6 wherein the means for applying one of the first and second periodic restorative forces comprises an elastic recoil of one of the inner member and outer tube.
 10. The apparatus of claim 8 further comprising at least one sensor operatively associated with one of the inner member and outer tube which generates a feedback signal relative to the orbital motion, the feedback signal being in communication with the electromagnetic drive mechanism.
 11. The apparatus of claim 10 further comprising control circuitry operatively associated with the at least one sensor which controls one of the first and second linear periodic forces and the first and second periodic restorative forces relative to the feedback signal from the sensor.
 12. An orbital fluid pumping mechanism, comprising: a. an outer tube having an inner surface; b. an inner member positioned substantially concentrically within the outer tube, the inner member having an outer surface; c. a helical lobe operatively associated with one of the inner surface of the outer tube and the outer surface of the inner member.
 13. The orbital fluid pumping mechanism of claim 12, further comprising means for orbiting one of the inner member and the outer tube relative to the other.
 14. The orbital fluid pumping mechanism of claim 13 wherein the helical lobe and one of the inner surface of the outer tube and the outer surface of the inner member are configured to cooperatively define an orbiting constriction between adjacent surfaces of the lobe and one of the inner surface of the outer tube and the outer surface of the inner member when the orbiting means is actuated, the orbiting constriction enabling pumping of a fluid.
 15. The orbital fluid pumping mechanism of claim 13 wherein the means for orbiting one of the inner member and outer tube comprises; means for applying a first periodic force at a select frequency to one of the inner member and outer tube along a first line of action; and means for applying a second periodic force to one of the inner member and outer tube at the select frequency, at a select phase shift from the first periodic force, along a second line of action which is transverse to the first line of action.
 16. The orbital fluid pumping mechanism of claim 15 further comprising; means for applying a first periodic restorative force at the select frequency to one of the inner member and outer tube along the first line of action; and means for applying a second periodic restorative force at the select frequency to one of the inner member and outer tube along the second line of action.
 17. The orbital fluid pumping mechanism of claim 15 wherein the second line of action is substantially orthogonal to the first line of action.
 18. The orbital fluid pumping mechanism of claim 16 wherein the means for applying one of the first and second periodic forces and the first and second periodic restorative forces comprises an electromagnetic drive mechanism.
 19. The orbital fluid pumping mechanism of claim 16 wherein the means for applying one of the first and second periodic restorative forces comprises an elastic recoil of one of the inner member and outer tube.
 20. The apparatus of claim 18 further comprising at least one sensor operatively associated with one of the inner member and outer tube which generates a feedback signal relative to the orbital motion, the feedback signal being in communication with the electromagnetic drive mechanism.
 21. The apparatus of claim 20 further comprising control circuitry operatively associated with the at least one sensor which controls one of the first and second linear periodic forces and the first and second periodic restorative forces relative to the feedback signal from the sensor.
 22. An orbital fluid pumping mechanism, comprising: a. an outer tube; b. an inner tube positioned concentrically within the outer tube; c. means for pumping fluid operatively associated with at least one of the inner tube and outer tubes; and d. means for orbiting one of the inner and outer tubes with respect to the other forming an orbiting tube.
 23. The orbital fluid pumping mechanism of claim 22 wherein the means for pumping fluid further comprises: a. an inner surface on the outer tube; b. an outer surface on the inner tube; c. a helical outer lobe operatively associated with the inner surface of the outer tube; and d. a helical inner lobe operatively associated with the outer surface of the inner tube, in operative association with the helical outer lobe.
 24. The orbital fluid pumping mechanism of claim 22 wherein the means for providing orbital motion comprises: means for applying a first periodic force to the orbiting tube at a select frequency along a first line of action; means for applying a second periodic force to the orbiting tube at the select frequency at a select phase shift from the first periodic force, along a second line of action which is transverse to the first line of action.
 25. The orbital fluid pumping mechanism of claim 22 further comprising; means for applying a first periodic restorative force at the select frequency to the orbiting tube along the first line of action; and means for applying a second periodic restorative force at the select frequency to the orbiting tube along the second line of action.
 26. The orbital fluid pumping mechanism of claim 23, wherein the helical outer lobe and the helical inner lobe are configured to cooperatively define an orbiting constriction between adjacent surfaces of the lobes when the orbiting tube is orbited, the orbiting constriction enabling pumping of a fluid.
 27. The orbital fluid pumping mechanism of claim 23, wherein the helical outer lobe and the helical inner lobe are configured to cooperatively define an orbiting seal between adjacent surfaces of the lobes when the orbiting tube is orbited, the orbiting seal enabling pumping of a fluid.
 28. The orbital fluid pumping mechanism of claim 24 wherein the select frequency substantially matches a fundamental resonant frequency of the orbiting tube.
 29. The orbital fluid pumping mechanism of claim 24 further comprising a support structure supporting the orbiting tube.
 30. The orbital fluid pumping mechanism of claim 29 wherein the support structure is configured so that a fundamental resonant frequency of the support structure is substantially different than the select frequency.
 31. The orbital fluid pumping mechanism of claim 29 further comprising a plurality of orbiting tubes, each supported by the support structure.
 32. The orbital fluid pumping mechanism of claim 31 wherein the plurality of orbiting tubes and the support structure are configured and the first and second linear periodic forces applied to each orbiting tube are timed such that a net torque applied to the support structures by the first and second linear periodic forces is minimized.
 33. The orbital fluid pumping mechanism claim 31 wherein the plurality of orbiting tubes and the support structure are configured and the first and second periodic forces applied to each orbiting tube are timed such that a net torque applied to the support structure by the first and second periodic forces is substantially zero.
 34. An apparatus for pumping fluid, comprising: a. a base; b. an outer tube mounted to the base at a fixed end and having a free end opposite the fixed end; c. an inner tube mounted to the base at a fixed end and having a free end opposite the fixed end, the inner tube being positioned substantially concentrically within the outer tube, thereby forming a cantilevered tube pair; and d. means for pumping fluid operatively associated with the inner and outer tubes.
 35. The apparatus for pumping fluid of claim 34 further comprising an outer housing attached to the base and forming a support structure with the base.
 36. The apparatus for pumping fluid of claim 34 further comprising means for imparting orbital motion to the free end of one of the inner and outer tubes causing an orbiting tube.
 37. The apparatus for pumping fluid of claim 36 wherein the means for imparting orbital motion to the orbiting tube comprises: means for applying a first periodic force to the orbiting tube at a select frequency along a first line of action; means for applying a second periodic force to the orbiting tube at the select frequency, at a select phase shift from the first periodic force, along a second line of action which is transverse to the first line of action.
 38. The apparatus for pumping fluid of claim 37 wherein the means for imparting orbital motion to the orbiting tube further comprises: means for applying a first periodic restorative force at the select frequency to the orbiting tube along the first line of action; and means for applying a second periodic restorative force at the select frequency to the orbiting tube along the second line of action.
 39. The apparatus for pumping fluid of claim 36 wherein the means for pumping fluid further comprises: a. an inner surface on the outer tube; b. an outer surface on the inner tube; c. a helical outer lobe in operative association with the inner surface of the outer tube; and d. a helical inner lobe in operative association with the outer surface of the inner tube in operative association with the helical outer lobe.
 40. The apparatus for pumping fluid of claim 39, wherein the helical outer lobe and the helical inner lobe are configured to cooperatively define an orbiting constriction between adjacent surfaces of the lobes when the means for imparting orbital motion is actuated, the orbiting constriction enabling pumping of a fluid.
 41. The apparatus for pumping fluid of claim 39, wherein the helical outer lobe and the helical inner lobe are configured to cooperatively define an orbiting seal between adjacent surfaces of the lobes when the means for imparting orbital motion is actuated, the orbiting seal enabling pumping of a fluid.
 42. The apparatus for pumping fluid of claim 39 wherein the select frequency substantially matches a fundamental resonant frequency of one of the inner and outer tubes.
 43. The apparatus for pumping fluid of claim 39 wherein the support structure is configured so that a fundamental resonant frequency of the support structure is substantially different than the select frequency.
 44. The apparatus for pumping fluid of claim 39 further comprising a plurality of cantilevered tube pairs, each attached to the base.
 45. The apparatus for pumping fluid of claim 44 wherein the plurality of cantilevered tube pairs and the support structure are configured and the first and second periodic forces applied to each cantilevered tube pair are timed such that a net torque applied to the base by the first and second periodic forces is minimized.
 46. The apparatus for pumping fluid of claim 44 wherein the plurality of cantilevered tube pairs and the support structure are configured and the first and second periodic forces applied to each cantilevered tube pair are timed such that a net torque applied to the base by the first and second periodic forces is substantially zero.
 47. An orbital apparatus for recovering energy from a fluid stream, comprising: a. an outer tube having an inner surface; b. an inner member positioned substantially concentrically within the outer tube, the inner member having an outer surface, the outer surface of the inner member and the inner surface of the outer tube defining an annular space; c. a fluid stream inlet to the annular space; d. a fluid stream outlet from the annular space; e. a helical outer lobe in operative association with the inner surface of the outer tube; and f. a helical inner lobe in operative association with the outer surface of the inner member in operative association with the helical inner lobe, the helical inner and outer lobes being located in fluid communication between the fluid stream inlet and the fluid stream outlet.
 48. The orbital apparatus of claim 47, wherein the helical outer lobe and the helical inner lobe are configured to cause orbital motion in at least one of the inner member and the outer tube upon providing a flow of fluid from the fluid stream inlet to the fluid stream outlet.
 49. The orbital apparatus of claim 48 further comprising means operatively associated with one of the inner member and the outer tube for recovering energy from the orbital motion caused by the flow of fluid from the fluid stream inlet to the fluid stream outlet.
 50. The orbital apparatus of claim 48 wherein the means for recovering energy from the orbital motion comprises: a wire coil and a magnet moving with respect to each other, the wire coil and magnet forming an inductive pair; and the inductive pair being operatively associated with one of the inner member, outer tube and support housing.
 51. The orbital apparatus of claim 48 wherein the means for recovering energy from the orbital motion comprises a mechanical linkage operatively associated with one of the inner member and outer tube.
 52. The orbital apparatus of claim 47 wherein the orbital apparatus operates as an expander in a fluid based cooling apparatus. 52.-68. (Cancelled) 